The goal of this proposal is to develop and evaluate an intuitive and ergonomically superior user interface for robotically-assisted ureteroscopy. Conventional ureteroscopy of the renal pelvis with a flexible endoscope is fraught with visualization, radiation exposure, and ergonomic challenges. This minimally invasive procedure enables stone removal, diagnosis for bleeding or malignancy, as well as direct biopsy and destruction of malignant tumors. For tumor inspection, the physician has to maneuver the ureteroscope through each of the 10 to 12 calyces in the kidney under fluoroscopy to keep track of the ureteroscope tip within the kidney. This involves estimating the 3D position of the ureteroscope using the 2D images from fluoroscopy. Moreover, ureteroscope control requires use of both hands, one to move the ureteroscope in and out and the other to rotate and flex the ureteroscope. Thus, there is great need for improved control and tracking of the flexible ureteroscope for this essential and common urologic procedure. Over the past two years, our research group has developed a robotic mechanical system that addresses some of these ergonomic challenges. This robotic assembly also provides a foundation to develop software and hardware to address the other challenges associated with ureteroscopy. The goal of this proposal is to develop and evaluate software for intuitive control of the robot using an affordable hardware interface device such as a joystick. The central hypothesis of this proposal is that development of a robotic system with an intuitive interface integrated with tracking capability wil allow for more efficient, ergonomic, and accurate ureteroscopy for kidney procedures. We will address this hypothesis through these two specific aims: Specific Aim 1: Extend our existing user interface for robotically assisted ureteroscopy to provide 3D tracking of the ureteroscope tip and improve the calibration between joystick movement and tip motion. These improvements should allow the urologist to easily, efficiently, and accurately control the ureteroscope. Specifi Aim 2: Evaluate the new user interface for effectiveness, efficiency, and user satisfaction using kidney phantoms. Once the interface is considered satisfactory by our urology team, we will compare urologist performance using our robotic system versus the conventional manual technique. Our long-term goal is the development of a hardware and software system that enables lower radiation exposure to the patients and hospital staff, effective tumor inspections, and a comfortable ergonomic experience for the physicians during ureteroscopy.